Sesquiterpene lactones and acetylenic derivatives from Artemisia nujianensis and their anti-inflammatory activity.

A phytochemical investigation of Artemisia nujianensis resulted in the isolation of fifteen compounds, comprising two eudesmane-type (1 and 5), two germacrene-type (2 and 3), and five guaiane-type (4 and 6-9) sesquiterpene lactones, together with four polyacetylenes (10-13) and two thiophene-containing acetylenes (14 and 15). Among these, four sesquiterpene lactones, artenujianenolides A-D (1-4), and one linear polyacetylene, artenujianenol A (10), are previously undescribed. Their structures were established through extensive spectroscopic analysis (1D and 2D NMR, HRESIMS) combined with quantum chemical calculations. In anti-inflammatory activity assays, compounds 1, 2, 5, 8, and 13 significantly inhibited nitric oxide (NO) production in LPS-stimulated RAW264.7 macrophages, with IC50 values in the range of 2.49-7.52 μM, compared with the positive control dexamethasone (IC50 = 0.21 ± 0.01 μM). These results not only enrich the structural diversity of the genus Artemisia and broaden the chemical space of sesquiterpene lactones and acetylenes, but also offer promising lead scaffolds for the development of anti-inflammatory agents.